Vane pump

摘要

A vane pump includes a casing and a rotary unit rotatably held within the casing. The rotary unit includes a base portion with radially outwardly opened slits extending radially with respect to a rotational axis of the rotary unit and vanes slidably fitted in the respective slits. An annular chamber is formed around the base portion within the casing and divided into a plurality of pump chambers by the vanes. Each of the pump chambers has a volume cyclically expanded and contracted during rotation of the rotary unit to discharge the fluid drawn into each of the pump chambers. The casing includes an inlet port through which to draw the fluid into the annular chamber. The inlet port is arranged to face a portion of the annular chamber extending between a middle position and a terminating position of an expanding section in which each of the pump chambers expands.